Measurement and correlation of solubilities for trifluoromethylbenzoic acid isomers in supercritical carbon dioxide

Higashi, Hidenori; Iwai, Yoshio; Miyazaki, Kaoru; OGINO, Y; OKI, M; Arai, Yasuhiko

doi:10.1016/s0896-8446(04)00097-x

Cited by 21 publications

(12 citation statements)

References 14 publications

(19 reference statements)

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“…The simulation results were compared with the interaction parameters in the PR-EOS which were used in a previous work [13]. The PR-EOS, combining and mixing rules used in the previous work [13] is written as follows:…”

Section: Resultsmentioning

confidence: 99%

“…The interaction parameters of the PR-EOS for the solute and solvent were adjusted by using solubility data [13] and these are shown in Table 2 …”

Section: Resultsmentioning

confidence: 99%

“…In a previous work [13], the authors measured the solubilities of 2-, 3-and 4-trifluoromethylbenzoic acids in supercritical carbon dioxide at 308.2, 313.2 and 323.2 K up to 22.6 MPa and compared those with non-fluorinated compounds. Solubility enhancements by fluorination were observed in the experimental results.…”

Section: Introductionmentioning

confidence: 99%

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Molecular dynamics simulation of fluorination effect for solvation of trifluoromethylbenzoic acid isomers in supercritical carbon dioxide

Higashi

Iwai

Miyazaki

et al. 2005

Molecular Simulation

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A molecular dynamics simulation was applied to carbon dioxide + trifluoromethylbenzoic acid isomer and carbon dioxide + methylbenzoic acid isomer systems to investigate the interactions between carbon dioxide and the solutes. The pair correlation functions between the carbon dioxide and trifluoromethyl group or methyl group in the solutes were calculated to study the fluorination effect of solvation. As a result, it was found that the interactions between carbon dioxide and trifluoromethyl group in trifluoromethylbenzoic acid isomers were stronger than those between carbon dioxide and the methyl group in methylbenzoic acid isomers. The simulation results had the same tendency as the experimental solubility enhancements and coincided with the trend of the interaction parameters of the Peng-Robinson equation of state that were determined from the solubility data.

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Section: Resultsmentioning

confidence: 99%

“…The interaction parameters of the PR-EOS for the solute and solvent were adjusted by using solubility data [13] and these are shown in Table 2 …”

Section: Resultsmentioning

confidence: 99%

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Molecular dynamics simulation of fluorination effect for solvation of trifluoromethylbenzoic acid isomers in supercritical carbon dioxide

Higashi

Iwai

Miyazaki

et al. 2005

Molecular Simulation

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“…In our previous works [14][15][16], NVT ensemble molecular dynamics simulation using spherical molecular model was successfully applied to calculate the self-diffusion coefficients of pure carbon dioxide and the tracer diffusion coefficients in carbon dioxide + aromatic compound systems. We showed that the spherical molecular model was applicable to calculate the self-and tracer diffusion coefficients for the given system by using parameters adjusted to the solubility.…”

Section: Introductionmentioning

confidence: 99%

“…Although n-decane is a chain-like molecule, we examined the spherical approximation for n-decane to simplify the NEMD calculation. In our previous works [14][15][16][17], we applied the spherical molecule model assumption to aromatic compounds and the spherical model was applicable to estimate solubility and diffusion coefficient of aromatic compounds in supercritical carbon dioxide.…”

Section: Introductionmentioning

confidence: 99%

Direct calculation of mutual diffusion coefficients of binary system using non-equilibrium molecular dynamics simulation

Higashi

Tamura

Seto

et al. 2015

Fluid Phase Equilibria

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Molecular dynamics (MD) simulation is widely used to calculate transport properties of fluids.In this study, non-equilibrium molecular dynamics (NEMD) simulation was applied to calculate mutual diffusion coefficients from the molecular flux at a given concentration gradient. First, the applicability of spherical molecular model was investigated by calculating self-and tracer diffusion coefficients of methane and n-decane mixture by a equilibrium MD simulation. The simulated self-and tracer diffusion coefficients of both components were in good agreement with literature data except in the case that methane molar fraction was nearly equal to zero. Further, the NEMD simulation was adopted to calculate mutual diffusion coefficients of binary system of methane and n-decane. This binary system exhibits anomalous concentration dependence of mutual diffusion coefficients in the vicinity of critical molar fraction according to the previously reported experimental data. The NEMD simulation well reproduced such concentration dependence of mutual diffusion coefficients.The simulation also gave a fairly good agreement with the calculated results by the Darken equation using tracer diffusion coefficients with a thermodynamic factor.

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Prediction of the Solubility of Cholesterol and its Esters in Supercritical Carbon Dioxide

Bozorgmehr

Housaindokht

2006

Chem Eng & Technol

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The ability to predict the solubility of solids in supercritical fluids is important in many applications, including the food and pharmaceutical industries, chemical processing, and separations. In the present work, the solubility of cholesterol and its esters in supercritical carbon dioxide are investigated by applying equations of state. The equations of state used are: (a) the modified Peng-Robinson equation of state (Gasem et al.), and (b) the modified Peng-Robinson equation of state (Boston and Mathias). These equations of state have an exponential alpha function and it is found that they give better results than those resulting from the Peng-Robinson equation of state which has a linear alpha function. The interaction parameters are also obtained for the systems studied and the percentage of average absolute relative deviation (%AARD) is displayed for each calculation. IntroductionSupercritical fluids (SCF) are widely applied to the extraction, separation and purification of pharmaceuticals, as well as the detoxification of hazardous wastes. Carbon dioxide is the most commonly used fluid for supercritical extraction, since it is nontoxic, nonflammable, easy to handle and has relatively low critical temperature and pressure [1].By using supercritical carbon dioxide, it is possible to extract thermally labile compounds, especially with pharmaceutical and food products. As an example, cholesterol can be removed from food products using supercritical solvent, resulting in minimal protein degradation [2]. Cholesterol, an integral component of membranes in Eucaryota, is a modifier of membrane properties. In vivo studies, have demonstrated that cholesterol can also modulate the activities of some G proteincoupled receptors, which are integral membrane proteins [3].Knowledge of the solubility of solids in SCF is essential to evaluate their extraction feasibility and to establish optimum operating conditions. However, solubility data of solids and their mixtures in SCF is limited and the accurate measurement of the solubility of solids in SCF is also difficult and time consuming. In efforts to widen the range of application, thermodynamic models capable of predicting phase equilibria become particularly important.Equations of state in combination with mixing rules are currently the most widely used models for the calculation of the solubility of components in SCF [4]. Some of the work reported in this area includes Gonzalo et al. [5], Valderrama and Alvarez [6], and Higashi et al. [7].In the present study, two modified versions of PR EOS are used to calculate the solubility of cholesterol and its esters in supercritical carbon dioxide. They are the modified PR EOS by Gasem et al. [8] and the modified PR EOS by Boston and Mathias [9], MPR1 and MPR2, respectively. The values of the interaction parameters in the binary systems studied in this work are presented and the percentage of average absolute relative deviation (%AARD) is displayed for each calculation. MethodsThe solubility of solids in SCF is given by 1):In ...

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Measurement and correlation of solubilities for trifluoromethylbenzoic acid isomers in supercritical carbon dioxide

Abstract: The solubilities of 2-, 3-and 4-trifluoromethylbenzoic acids in supercritical carbon dioxide were measured at 308.2, 313.2 and 323.2 K by a flow-type apparatus. The pressure range of the measurement was from 9 to 23 MPa.

Cited by 21 publications

References 14 publications

Molecular dynamics simulation of fluorination effect for solvation of trifluoromethylbenzoic acid isomers in supercritical carbon dioxide

Molecular dynamics simulation of fluorination effect for solvation of trifluoromethylbenzoic acid isomers in supercritical carbon dioxide

Direct calculation of mutual diffusion coefficients of binary system using non-equilibrium molecular dynamics simulation

Prediction of the Solubility of Cholesterol and its Esters in Supercritical Carbon Dioxide

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